Hot-air furnace



Apr. 24, 1923. 1,453,063

- J. CHALMERS HOT AIR FURNACE Filed Nov. 16, 1921' we Fl' -L F5 w IE 4 5 \7 6 40 5 v IIIIII/ Patented Apr. 24, 1923.

@NHTED STATES JOHN CHALIEERS, OF VANCOUVER, BRITISH COLUMBIA, CANADA.

HOT-AIR FURNACE.

Application filed November 16, 1921.

T 0 all whom it may concern:

Be it known that 1, JOHN CHALMERs, of

the city of Vancouver,,Province of British Columbia, Dominion of Canada, a subject of the King of Great Britain, have invented certain new and useful Improvements in Hot-Air Furnaces; and I do hereby declare that the following is a full, clear, and exact description thereof.

The objects of my invention are firstly, to provide a furnace of the hot air type in which the air is more quickly heated and a greater amount of heat is obtained wlth a lesser amount of fuel than has been possible in hot air furnaces heretofore in use, secondly, to provide a furnace in which the exhaust gases will be prevented from mixing with the air being heated, and thirdly, to provide a furnace which can be manufactured at minimum cost.

To this end my invention consists of the particular construction and arrangement of parts hereinafter described, illustrated and pointed out in the claims.

For full comprehension, however, of my invention reference must be had to the accompanying drawing in which similar reference characters indicate the same parts, and wherein- Figure 1 is a longitudinal sectional view partly in elevation of a hot air furnace constructed according to my invention;

Figure 2 is an end elevation thereof;

Figure 3 is a transverse sectional view taken on line 3-3 Figure 1;

Figure 4: is a transverse sectional view taken on line i4 Figure 1; and

Figure 5 is a transverse sectional view taken on line 5-5 Figure 1.

The embodiment illustrated in the accompanying drawing discloses a hot-air furnace employing oil as a fuel. It is tobe distinctly understood, however, that the furnace may be adapted to the burning of other fuel without departing from the spirit of my invention.

The furnace illustrated consists of a horizontally-disposed heat generating chamber or fire-pot 2 having a refractory lining 3the respective ends of which are closed by a' removable metal plate 4: and a fitting 5 of truncated conical form, the larger end of the fitting having a circumferential flange 6 which is riveted or otherwise secured to the adjacent end of the fire-pot as at 7 The truncated end is flanged as at 8 and is adapted Serial No. 515,607.

to be secured to the correspondingly flanged end of a pipe 9 through which the exhaust gases are permitted to escape.

Surrounding the fire-pot is a circuitous conductor through which the air to be heated is passed before being distributed. This conductor is constituted by preferably two hollow cylindrical casings 10 and 12 nested or positioned one within the other and encircling the fire-pot and extending throughout the length of the same. The outer casing 12 is of a greater diameterthan that of the inner casing 10 and the latter of a greater diameter than the outside diameter of the fire-pot to provide cylindrical spaces 13 and ll-therebetween which are closed at one'end by the end plate 4: and at the opposite end by the flange 6 on the fitting 5 and by a circumferential flange 17 on a cap 18 enclosing the fitting, the cap being bolted to the outer casing 12 as at 19 and communicating with the conductor through an opening l0 in the flange 6. The outer end of the cap has an opening 20 therein through which the truncated end of the fitting 5 projects, the opening being sufficiently large to provide a passage for the heated air as it passes from the furnace into the distribution pipe 21 which is of comparatively large diameter and extends parallel to and encloses'the pipe 9,

being secured to the cap as at 22. Registers 23 may be located in thepipe 21 at any desired. point.

In order to cause the air to follow a zigor tortuous course. within the spaces 13 and 14, the latter are divided by a plurality of longitudinal uniformly-spaced radiallyextending partitions 15 into inner and outer nested series of inter-communicating passages, communication between the two series being effected through an opening or port.

16 in the inner casing 10 at one end thereof. Communication between the ad oinlng passages of each series is effected by openings 24 arranged in staggered relation, that is to say, the openings in the successive partitions are alternately positioned at opposite ends eating with one of the passages of the outer series, such passage being indicated at 28. and the outer casing having an inlet 29 to which the branch 26 is connected. The opening 24;, effecting communication between passage 28 and that immediately adjacent, is located at the end of the passage opposite to that with which the inlet 29 communicates.

Th branch connection 27 leads to an oilburner 30 which is mounted in a central hub 31. formed integrally with the closure 4. The oil supply-pipe leading to the burner is indicated at 32 and is controlled by a valve A blower 34: is connected to the pipe 25 and is adapted to drive the air therethrough to the burner and conductor.

The size and number of the passages may be varied according to the volume of air re quired and they may be disposed transversely to the length of the fire pot without departing from the spirit of the invention.

An insulating covering may be applied to the outermost casing if desired.

Operation.

In the operation of this invention, upon the burner 30 being lighted and the blower 34 set in motion, air is driven through pipe 25 and branch connections 26 and 27 to the burner and conductor, respectively. It enters the conductor through inlet 29 and flows along passage 28 passing through opening 24 at the opposite end thereof into the next adjoining passage. After following a zigzag course through the passages of the outer series it passes into the inner series through opening 16. After flowing through the passages of the inner series it passes into cap 18 through opening from whence it flows into distribution pipe 21 through opening 20. The pipe 9 being of metal assists in raising thetemperature of the air as it passes through the pipe 21 to the registers.

It will be seen from this construction that a continuous conductor of Zigzag form is provided within the zone of heat of the fire pot and the air flowing therethrough derives the full benefit of such heat before being distributed.

hat I claim is as follows:

1. The combination with a heat generating chamber; and a continuous air conduc tor surrounding the chamber. said conductor comprising a series of longitudinal passages of segmental cross-section collectively forming an annular unit surrounding the heat generating chamber, each passage having an inlet at one end and an outlet. at its opposite end, the outlet communicating with the inlet of the next succeeding passage thereby forming a continuous zigzag conductor. a blower located in position exteriorly of the furnace, and means effecting communication between the air conductor and blower for the purpose of supplying fresh air thereto.

2. A hot air furnace consisting of a heat generating chamber, an air conductor surrounding the chamber said conductor being distinct from and having no communication with thechamber, and means for supplying fresh air to the conductor, sald means consisting of a blower located in posi tion cxteriorly of the furnace and a pipe efiecting communication between the blower and air conductor.

3. A hot air furnace consisting of a heat generating chamber, having an exhaustpipe for the discharge of the exhaust gases, a burner in said chamber, a fuel pipe communicating with the burner, an air conductor surrounding the chamber, said conductor being distinct from the chamber and exhaust pipe and having no communication therewith, and means for supplying fresh air to the conductor, said means consisting of a blower located in position exteriorly of the furnace, an air supply pipe efl'ecting communication between the blower and the burner, and a second air supply pipe effecting communication between the blower and conductor, and a hot air distribution duct leading from the conductor to the point to be heated. said duct having no communication with the exhaust pipe.

42. In a furnace of the type described the combination with a fire-pot, a fitting closing one end. of said fire-pot, a pipe connected to the fitting and adapted to permit the escape of the exhaustgases from the fire-pot a plate closing the opposite end of said firepot, a burner mounted in said plate, a fuel supply pipe connected to said burner; an air conductor surrounding said fire-pot and consisting. of a plurality of nested casings with closed ends encirclingthe fire-pot and extending throughout the length of the same, said casings being spaced from each other and from the fire-pot, a plurality of uniformly spaced partitions dividing the spaces between the casings and casings and fire-pot into inner and outer series of passages, the partitions separating the adjoining passages of each series having openings therein, an air-supply pipe connected to said burner and said air-conductor, a blower connected to said supply pipe, and a comparatively large duct encircling the exhaust pipe connected. to said fitting, said comparatively large duct being connected to the air conductor.

5. In a furnace of the type described the combination with a cylindrical fire-pot, a fitting of truncated conical form closing one end of said fire-pot. a pipe connected to the truncated end of said fitting and adapted to permit the escape of the exhaust gases from the firepot a plate closing the opposite end of said fire-pot and having a central hub, a burner mounted in said hub, a fuel supply pipe connected to said burner; of an air-conductor surrounding said fire-pot and consisting of a plurality of nested cylindrical casings encircling the fire-pot and L viding the spaces between the casings and casings and fire-pot into inner and outer series of passages, the partitions separating the adjoining passages of each series having openings therein, an air-supply pipe connected to said burner and said air-conductor and a blower connected to said supply pipe, a circumferential flange upon said truncated fitting closing one end of the space between the innermost casing and the firepot, said flange having an outlet opening therein, a hollow cap enclosing said fitting and having a circumferential flange closing the adjacent end of the space between the innermost and outermost casings, the opposite end of said last-mentioned space and the space between the innermost casing and fire-pot being closed by said plate, and a comparatively large duct extending parallel to and encircling the pipe connected to said truncated fitting, said comparatively large duct being connected to said cap and being in communication with the interior thereof, substantially as described.

In testimony whereof I have signed my name to this specification in the presence of two witnesses:

JOHN CHALMERS. Witnesses:

MARIAN P. BUSH, FRED S. WEAVER. 

